Method and circuit for use by a handheld multiple function device

ABSTRACT

A method for use in a multifunction handheld device includes receiving a plurality of digitally formatted files from a host device when coupled to the host device. A selected one of the plurality of digitally formatted files is played, the playing includes generating an audio output. The method monitors for a low voltage condition produced by a low battery voltage. When the low voltage condition is detected, a first fail safe algorithm is enabled to store an audio setting corresponding to the playing of the audio output, and to shutdown the multifunction handheld device, so that later, when the playback can be resumed, the playback can continue based on the stored audio setting.

This patent is claiming priority under 35 USC § 119(e) to provisionallyfiled patent application entitled MULTI-FUNCTION HANDHELD DEVICE, havinga provisional Ser. No. of 60/429,941 and a provisional filing date ofNov. 29, 2002.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to portable electronic equipment andmore particularly to efficient powering of such devices.

2. Description of Related Art

As is known, integrated circuits are used in a wide variety ofelectronic equipment, including portable, or handheld, devices. Suchhandheld devices include personal digital assistants (PDA), CD players,MP3 players, DVD players, AM/FM radio, a pager, cellular telephones,computer memory extension (commonly referred to as a thumb drive), etc.Each of these handheld devices include one or more integrated circuitsto provide the functionality of the device. For example, a thumb drivemay include an integrated circuit for interfacing with a computer (e.g.,personal computer, laptop, server, workstation, etc.) via one of theports of the computer (e.g., Universal Serial Bus, parallel port, etc.)and at least one other memory integrated circuit (e.g., flash memory).As such, when the thumb drive is coupled to a computer, data can be readfrom and written to the memory of the thumb drive. Accordingly, a usermay store personalized information (e.g., presentations, Internet accessaccount information, etc.) on his/her thumb drive and use any computerto access the information.

As another example, an MP3 player may include multiple integratedcircuits to support the storage and playback of digitally formattedaudio (i.e., formatted in accordance with the MP3 specification). As isknown, one integrated circuit may be used for interfacing with acomputer, another integrated circuit for generating a power supplyvoltage, another for processing the storage and/or playback of thedigitally formatted audio data, and still another for rendering theplayback of the digitally formatted audio data audible.

Integrated circuits have enabled the creation of a plethora of handhelddevices, however, to be “wired” in today's electronic world, a personneeds to posses multiple handheld devices. For example, one may own acellular telephone for cellular telephone service, a PDA for scheduling,address book, etc., one or more thumb drives for extended memoryfunctionality, an MP3 player for storage and/or playback of digitallyrecorded music, a radio, etc. Thus, even though a single handheld devicemay be relatively small, carrying multiple handheld devices on one'sperson can become quite burdensome.

A vital concern with every battery powered handheld device is itsbattery life (i.e., how long the handheld device will run before thebattery has to be replaced). There are two primary components toextending the battery life of a handheld device: one is to minimizepower consumption and the other is to use the battery to its fullestcapacity. Most of the efforts to date with respect to battery life havebeen focused on reducing power consumption. While this is extremelyimportant, using the battery to its fullest extent is becoming morecritical and getting some attention.

Current techniques to use the battery to its fullest extent safely(i.e., shutting down the handheld device in a safe manner when thebattery is consumed) monitor the battery voltage. When the batteryvoltage drops below a threshold, the handheld device is shutdown bystoring current user settings et cetera such that when the battery isreplaced, the handheld device comes up in a known manner and, ifdesired, where it left off just before the battery was replaced. If thehandheld device is not shutdown in a known manner when the batteryvoltage drops below the threshold, the software of the handheld devicemay lock-up causing the handheld device to require service.

While monitoring the battery voltage does provide a safe shutdownmechanism extending the usefulness of a battery, it does not enable thebattery to be used to its fullest extent, nor does it distinguish thepossible reasons as to why the battery voltage dropped.

Therefore, a need exists for a method and apparatus that maximizesbattery life based on operating conditions of a battery powered handhelddevice.

BRIEF SUMMARY OF THE INVENTION

The method and apparatus for efficient battery use by a handheldmultifunction device of the present invention substantially meets theseneeds and others. In one embodiment, a method for efficient battery usebegins by monitoring at least one output of the handheld device for anoverload condition. For example, the headphone jack output may bemonitored for an overload condition, which may be caused by an improperinstallation of a headphone, a short, et cetera. The processingcontinues by monitoring a system voltage produced by a DC-to-DCconverter for a system low voltage condition. For example, based on thepower requirements to be sourced by the DC-to-DC converter, the DC-to-DCconverter is overloaded such that its output voltage is drooping. Theprocess continues by monitoring voltage of the battery for a battery lowvoltage condition. For example, the battery voltage may be monitored forfalling below a threshold, which may result from extended use or failingto make adequate electrical contact with the terminals of the handhelddevice. The processing then continues by enabling one of a plurality offail-safe algorithms based on when one or more of the overloadcondition, the system low voltage condition, and/or the battery lowvoltage condition are detected. With such a method, and/or apparatusincorporating such a method, the battery life of a handheld device maybe taken to its fullest extent and just before the battery hasinsufficient power to power the handheld device, the handheld device ispartially or fully shutdown in a safe manner.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a multifunction handheld devicein accordance with the present invention;

FIG. 2 is a schematic block diagram of another multifunction handhelddevice in accordance with the present invention;

FIG. 3 is a schematic block diagram of an integrated circuit for use ina multifunction handheld device in accordance with the presentinvention;

FIG. 4 is a schematic block diagram of another integrated circuit foruse in a multifunction handheld device in accordance with the presentinvention;

FIG. 5 is a schematic block diagram of the handheld device providingefficient battery use in accordance with the present invention;

FIG. 6 is a graph plotting battery consumption versus battery voltage;

FIG. 7 is a graph plotting supply voltage versus power consumption forCMOS integrated circuits;

FIG. 8 is a logic diagram of a method for efficient battery use by ahandheld device in accordance with the present invention; and

FIGS. 9-12 are logic diagrams regarding the plurality of fail-safealgorithms that may be performed in accordance with the method of FIG.8.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of a multi-function handheld device10 and corresponding integrated circuit 12 operably coupled to a hostdevice A, B, or C. The multi-function handheld device 10 also includesmemory integrated circuit (IC) 16 and a battery 14. The integratedcircuit 12 includes a host interface 18, a processing module 20, amemory interface 22, a multimedia module 24, a DC-to-DC converter 26,and a bus 28. The multimedia module 24 alone or in combination with theprocessing module 20 provides the functional circuitry for theintegrated circuit 12. The DC-to-DC converter 26, which may beconstructed in accordance with the teaching of U.S. Pat. No. 6,204,651,entitled METHOD AND APPARATUS FOR REGULATING A DC VOLTAGE, provides atleast a first supply voltage to one or more of the host interface 18,the processing module 20, the multimedia module 24, and the memoryinterface 22. The DC-to-DC converter 26 may also provide V_(DD) to oneor more of the other components of the handheld device 10.

When the multi-function handheld device 10 is operably coupled to a hostdevice A, B, or C, which may be a personal computer, workstation, server(which are represented by host device A), a laptop computer (host deviceB), a personal digital assistant (host device C), and/or any otherdevice that may transceive data with the multi-function handheld device,the processing module 20 performs at least one algorithm 30, where thecorresponding operational instructions of the algorithm 30 are stored inmemory 16 and/or in memory incorporated in the processing module 20. Theprocessing module 20 may be a single processing device or a plurality ofprocessing devices. Such a processing device may be a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The associated memory may bea single memory device or a plurality of memory devices. Such a memorydevice may be a read-only memory, random access memory, volatile memory,non-volatile memory, static memory, dynamic memory, flash memory, and/orany device that stores digital information. Note that when theprocessing module 20 implements one or more of its functions via a statemachine, analog circuitry, digital circuitry, and/or logic circuitry,the associated memory storing the corresponding operational instructionsis embedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry.

With the multi-function handheld device 10 in the first functional mode,the integrated circuit 12 facilitates the transfer of data between thehost device A, B, or C and memory 16, which may be non-volatile memory(e.g., flash memory, disk memory, SDRAM) and/or volatile memory (e.g.,DRAM). In one embodiment, the memory IC 16 is a NAND flash memory thatstores both data and the operational instructions of at least some ofthe algorithms 30.

In this mode, the processing module 30 retrieves a first set ofoperational instructions (e.g., a file system algorithm, which is knownin the art) from the memory 16 to coordinate the transfer of data. Forexample, data received from the host device A, B, or C (e.g., Rx data)is first received via the host interface module 18. Depending on thetype of coupling between the host device and the handheld device 10, thereceived data will be formatted in a particular manner. For example, ifthe handheld device 10 is coupled to the host device via a USB cable,the received data will be in accordance with the format proscribed bythe USB specification. The host interface module 18 converts the formatof the received data (e.g., USB format) into a desired format byremoving overhead data that corresponds to the format of the receiveddata and storing the remaining data as data words. The size of the datawords generally corresponds directly to, or a multiple of, the bus widthof bus 28 and the word line size (i.e., the size of data stored in aline of memory) of memory 16. Under the control of the processing module20, the data words are provided, via the memory interface 22, to memory16 for storage. In this mode, the handheld device 10 is functioning asextended memory of the host device (e.g., like a thumb drive).

In furtherance of the first functional mode, the host device mayretrieve data (e.g., Tx data) from memory 16 as if the memory were partof the computer. Accordingly, the host device provides a read command tothe handheld device, which is received via the host interface 18. Thehost interface 18 converts the read request into a generic format andprovides the request to the processing module 20. The processing module20 interprets the read request and coordinates the retrieval of therequested data from memory 16 via the memory interface 22. The retrieveddata (e.g., Tx data) is provided to the host interface 18, whichconverts the format of the retrieved data from the generic format of thehandheld device into the format of the coupling between the handhelddevice and the host device. The host interface 18 then provides theformatted data to the host device via the coupling.

The coupling between the host device and the handheld device may be awireless connection or a wired connection. For instance, a wirelessconnection may be in accordance with Bluetooth, IEEE 802.11(a), (b) or(g), and/or any other wireless LAN (local area network) protocol, IrDA,etc. The wired connection may be in accordance with one or more Ethernetprotocols, Firewire, USB, etc. Depending on the particular type ofconnection, the host interface module 18 includes a correspondingencoder and decoder. For example, when the handheld device 10 is coupledto the host device via a USB cable, the host interface module 18includes a USB encoder and a USB decoder.

As one of average skill in the art will appreciate, the data stored inmemory 16, which may have 64 Mbytes or greater of storage capacity, maybe text files, presentation files, user profile information for accessto varies computer services (e.g., Internet access, email, etc.),digital audio files (e.g., MP3 files, WMA—Windows Media Architecture—,MP3 PRO, Ogg Vorbis, AAC—Advanced Audio Coding), digital video files[e.g., still images or motion video such as MPEG (motion picture expertgroup) files, JPEG (joint photographic expert group) files, etc.],address book information, and/or any other type of information that maybe stored in a digital format. As one of average skill in the art willfurther appreciate, when the handheld device 10 is coupled to the hostdevice A, B, or C, the host device may power the handheld device 10 suchthat the battery is unused.

When the handheld device 10 is not coupled to the host device, theprocessing module 20 executes an algorithm 30 to detect thedisconnection and to place the handheld device in a second operationalmode. In the second operational mode, the processing module 20retrieves, and subsequently executes, a second set of operationalinstructions from memory 16 to support the second operational mode. Forexample, the second operational mode may correspond to MP3 fileplayback, digital dictaphone recording, MPEG file playback, JPEG fileplayback, text messaging display, cellular telephone functionality,and/or AM/FM radio reception. Each of these functions is known in theart, thus no further discussion of the particular implementation ofthese functions will be provided except to further illustrate theconcepts of the present invention.

In the second operational mode, under the control of the processingmodule 20 executing the second set of operational instructions, themultimedia module 24 retrieves multimedia data 34 from memory 16. Themultimedia data 34 includes at least one of digitized audio data,digital video data, and text data. Upon retrieval of the multimediadata, the multimedia module 24 converts the data 34 into rendered outputdata 36. For example, the multimedia module 24 may convert digitizeddata into analog signals that are subsequently rendered audible via aspeaker or via a headphone jack. In addition, or in the alternative, themultimedia module 24 may render digital video data and/or digital textdata into RGB (red-green-blue), YUV, etc., data for display on an LCD(liquid crystal display) monitor, projection CRT, and/or on a plasmatype display. The multimedia module 24 will be described in greaterdetail with reference to FIGS. 2 and 3.

As one of average skill in the art, the handheld device 10 may bepackaged similarly to a thumb drive, a cellular telephone, pager (e.g.,text messaging), a PDA, an MP3 player, a radio, and/or a digitaldictaphone and offer the corresponding functions of multiple ones of thehandheld devices (e.g., provide a combination of a thumb drive and MP3player/recorder, a combination of a thumb drive, MP3 player/recorder,and a radio, a combination of a thumb drive, MP3 player/recorder, and adigital dictaphone, combination of a thumb drive, MP3 player/recorder,radio, digital dictaphone, and cellular telephone, etc.).

FIG. 2 is a schematic block diagram of another handheld device 40 and acorresponding integrated circuit 12-1. In this embodiment, the handhelddevice 40 includes the integrated circuit 12-1, the battery 14, thememory 16, a crystal clock source 42, one or more multimedia inputdevices (e.g., one or more video capture device(s) 44, keypad(s) 54,microphone(s) 46, etc.), and one or more multimedia output devices(e.g., one or more video and/or text display(s) 48, speaker(s) 50,headphone jack(s) 52, etc.). The integrated circuit 12-1 includes thehost interface 18, the processing module 20, the memory interface 22,the multimedia module 24, the DC-to-DC converter 26, and a clockgenerator 56, which produces a clock signal (CLK) for use by the othermodules. As one of average skill in the art will appreciate, the clocksignal CLK may include multiple synchronized clock signals at varyingrates for the various operations of the multi-function handheld device.

Handheld device 40 functions in a similar manner as handheld device 10when exchanging data with the host device (i.e., when the handhelddevice is in the first operational mode). In addition, while in thefirst operational mode, the handheld device 40 may store digitalinformation received via one of the multimedia input devices 44, 46, and54. For example, a voice recording received via the microphone 46 may beprovided as multimedia input data 58, digitized via the multimediamodule 24 and digitally stored in memory 16. Similarly, video recordingsmay be captured via the video capture device 44 (e.g., a digital camera,a camcorder, VCR output, DVD output, etc.) and processed by themultimedia module 24 for storage as digital video data in memory 16.Further, the key pad 54 (which may be a keyboard, touch screeninterface, or other mechanism for inputting text information) providestext data to the multimedia module 24 for storage as digital text datain memory 16. In this extension of the first operational mode, theprocessing module 20 arbitrates write access to the memory 16 among thevarious input sources (e.g., the host and the multimedia module).

When the handheld device 40 is in the second operational mode (i.e., notconnected to the host), the handheld device may record and/or playbackmultimedia data stored in the memory 16. Note that the data provided bythe host when the handheld device 40 was in the first operational modeincludes the multimedia data. The playback of the multimedia data issimilar to the playback described with reference to the handheld device10 of FIG. 1. In this embodiment, depending on the type of multimediadata 34, the rendered output data 36 may be provided to one or more ofthe multimedia output devices. For example, rendered audio data may beprovided to the headphone jack 52 an/or to the speaker 50, whilerendered video and/or text data may be provided to the display 48.

The handheld device 40 may also record multimedia data 34 while in thesecond operational mode. For example, the handheld device 40 may storedigital information received via one of the multimedia input devices 44,46, and 54.

FIG. 3 is a schematic block diagram of an integrated circuit 12-2 thatmay be used in a multi-function handheld device. The integrated circuit12-2 includes the host interface 18, the processing module 20, theDC-to-DC converter 26, memory 60, the clock generator 56, the memoryinterface 22, the bus 28 and the multimedia module 24. The DC-to-DCconverter 26 includes a first output section 62, and a second outputsection 64 to produce a first and second output voltage (V_(DD1) andV_(DD2)), respectively. Typically, V_(DD1) will be greater that V_(DD2),where V_(DD1) is used to source analog sections of the processing module20, the host interface 18, the memory interface 22, and/or themultimedia module 22 and V_(DD2) is used to source the digital sectionsof these modules. The DC-to-DC converter 26 may further include abattery charger 63 and a low loss multiple output stage 62. The batterycharger 63 is operable to charge the battery 14 from power it receivesvia the physical coupling (e.g., via a USB cable) to the host devicewhen the multi-function handheld device is physically coupled to thehost device. The particular implementation of the battery charger 63 isdependent on the type of battery being used and such implementations areknown in the art, thus no further discussion will be provided regardingthe battery charger 63 except to further illustrate the concepts of thepresent invention.

The multimedia module 24 includes an analog input port 66, an analog todigital converter (ADC) 68, an analog output port 70, a digital toanalog converter (DAC) 72, a digital input port 74, a digital outputport 76, and an analog mixing module 78. The analog input port 66 isoperably coupled to receive analog input signals from one or moresources including a microphone, an AM/FM tuner, a line in connection(e.g., headphone jack of a CD player), etc. The received analog signalsare provided to the ADC 68, which produces digital input data therefrom.The digital input data may be in a pulse code modulated (PCM) format andstored as such, or it may be provided to the processing module 20 forfurther audio processing (e.g., compression, MP3 formatting, etc.) Thedigital input data, or the processed version thereof, is stored inmemory 16 as instructed by the processing module 20.

The digital input port 74 is operably coupled to receive digital audioand/or video input signals from, for example, a digital camera, acamcorder, etc. The digital audio and/or video input signals may bestored in memory 16 under the control of the processing module 20. Asone of average skill in the art will appreciate, the audio and/or videodata (which was inputted as analog signals or digital signals) may bestored as raw data (i.e., the signals received are stored as is indesignated memory locations) or it may be stored as processed data(i.e., compressed data, MPEG data, MP3 data, WMA data, etc.).

The DAC 72 receives multimedia data 34 as digital output data andconverts it into analog video and/or audio output data that is providedto the mixing module 78. When the output of the DAC 72 is the only inputto the mixing module 78, the mixing module 78 outputs the analog videoand/or audio output data to the analog output port 70. The analog outputport 70 may be coupled to one or more of the speaker, headphone jack,and a video display. The mixing module 78 may mix analog input signalsreceived via the analog input port 66 with the output of DAC 72 toproduce a mixed analog signal that is provided to the analog output port70. Note that the buffers in series with the inputs of the mixing module78 may have their gains adjusted and/or muted to enable selection of thesignals at various gain settings provided to the mixing module 78 andsubsequently outputted via the analog output port 70.

The digital output port 76 is operably coupled to output the digitaloutput data (i.e., the multimedia data 34 in a digital format). Thedigital output port 76 may be coupled to a digital input of a videodisplay device, another handheld device for direct file transfer, etc.

As one of average skill in the art will appreciate, the multimediamodule 24 may include more or less components than the components shownin FIG. 3 or include multiple analog and/or digital input and/or outputports. For example, for a playback mode of digital audio files, themultimedia module 24 may only include the DAC 72 and the analog outputport 70 that is coupled to the headphone jack and/or to the speaker. Asanother example, for recording voice samples (i.e., as a digitaldictaphone), the multimedia module 24 may include the analog input port66 coupled to the microphone and the ADC.

FIG. 4 is a schematic block diagram of an integrated circuit 12-3 thatmay be incorporated in a multi-function handheld device 10 or 40. Theintegrated circuit 12-3 includes a general purpose input/output module80, a CD control interface 82, an I²C interface module 84, a displayinterface module 86, a static and/or dynamic RAM interface 88, an inputinterface module 90, processing module 20, ROM 35, RAM 33, a peripheralbus 104, a memory bus 106, a system-on-a-chip (SOC) management module100, a universal serial bus (USB) interface 102, a digital-to-analogconverter 72, an analog-to-digital converter 68, a multiplexer, buffers,mixing module 78, DC to DC converter 26, a programmable driver 92, and amicrophone bias module 96.

In operation, the integrated circuit 12-3 may facilitate thetransceiving of data with a host device between system memory of amulti-function handheld device and a host device, may playbackmultimedia data, and/or may record multimedia data via input ports. Whenthe integrated circuit 12-3 is transceiving with a host device, the USBinterface 102 operably couples the integrated circuit 12-3 to a hostdevice. In addition, the SDRAM interface 88 couples, either via thegeneral purpose input/output module 80 or directly, to the system memory(e.g., memory IC 16) of the multi-function handheld device 10. In thisconfiguration, data that is received from the host device is placed onthe memory bus 106 by the USB interface 102. The SDRAM interface 88retrieves the data from the memory bus 106 and forwards it for storageto the system memory under the control of the processing module 20 thatis executing a file system storage algorithm. The data being stored maycorrespond to playback data, such as an MP3 file, a WMA file, a videofile, a text file, and/or a combination thereof. Alternatively, or inaddition to, the data being received from the host may correspond toprogramming instructions of an algorithm 30, which may be an MP3 decoderalgorithm, a WMA decoder algorithm, a MPEG algorithm, a JPEG algorithm,et cetera.

For providing data from the handheld device 10 to the host device, theSDRAM interface 88 retrieves data from the system memory and places iton the memory bus 106 under the control of the processing module 20 asit executes a file system algorithm. The USB interface 102 retrieves thedata from the memory bus 106 and forwards it to the host device inaccordance with one of the versions of the USB standard.

Data may also be stored in the system memory that is received via the CD(compact disk) control interface 82, and/or the I²C interface 84 orother type of two or three wire data interface. Via these interfaces 82and 84, data is received via the general purpose input/output module 80and placed on the memory bus 106. The SDRAM interface 88 retrieves thedata from the memory bus 106 and provides it to the system memory, whichis done under the control of the processing module as it executes a datastorage algorithm.

When the integrated circuit 12-3 is recording audio inputs received viathe microphone input, the microphone bias circuit 96 provides thereceived audio signals to the mixing module 78 as well as to themultiplexer (mux) via a buffer. The microphone bias circuit 96 biasesthe audio input for optimal operations. The received audio input signalsare is converted to digital audio signals via the analog-to-digitalconverter 68. The digital audio signals may then be stored in systemmemory (e.g., memory IC 16). Alternatively, the audio input signal maybe provided to the summing module 78 and subsequently provided toheadphone jack 94 via the programmable driver 92 as a component of asummed analog signal. The summing module 78 may sum, or pass any one of,the audio input signals may be mixed with other analog input signals,such as a line input, an FM radio input, and the analog output of theDAC 72, to produce the summed signal.

When the integrated circuit 12-3 is in a playback mode, digitalmultimedia data is retrieved from the system memory and provided to thedigital-to-analog converter 72. The digital-to-analog converter 72converts the digital multimedia signals, which may be audio data, videodata and/or text data, into analog multimedia signals and provides theanalog multimedia signals to mixing module 78. In the playback mode, themixing module 78 will generally have the other inputs muted, such thatits output corresponds directly to the analog multimedia signalsprovided by the digital-to-analog converter 72.

The programmable driver 92 increases the drive power of the analogmultimedia signals (e.g., audio signals when the analog multimediasignals are provided to a headphone) and provides it to the headphonejack 94. As one of average skill in the art will appreciate, a fixeddriver may replace the programmable driver 92 to drive the headphonejack 94.

To place the integrated circuit 12-3 into the various operational modes,commands are received via the general purpose input/output module 80 bythe input interface 90. The input interface 90 receives the inputstimulus corresponding to commands, interprets the input stimulus togenerate the corresponding commands. The commands are then provided onthe peripheral bus 104 and/or the memory bus 106 and processed by theprocessing module 20.

In addition to producing audio outputs during playback mode, theintegrated circuit 12-3 may provide video outputs via the displayinterface 86, which will be described in greater detail with referenceto FIG. 14. The display interface 86 drives the display, which may be anLCD display, LED display, plasma display and/or any other type ofdisplay. The data being displayed may correspond to the multimedia dataretrieved from the system memory, and/or may correspond to the commandsinputted via the input interface 90.

The system-on-a-chip (SOC) management module 100 processes interruptcontrols, generates clock signals for the integrated circuit 12-3,performs bit manipulations, performs debugging operations, and executesa Reed-Solomon, or other type of encoding/decoding algorithm to encodeand/or decode data.

The DC-to-DC converter 26 provides at least one supply voltage for theintegrated circuit 12-3 and typically provides two supply voltages. Forexample, the DC-to-DC converter 26 may produce a 3.3 volts supply and a1.8 volt supply.

FIG. 5 is a schematic block diagram of the handheld device of FIGS. 1and/or 2 consuming power and managing the power consumption to provideefficient battery use in accordance with the present invention. Asshown, battery 14 produces a battery voltage that, via a switch, iscoupled to the DC-to-DC converter 26. The DC-to-DC converter produces asystem voltage 112 which may correspond to V_(DD) 1 or V_(DD) 2 as shownin FIGS. 1-4. The multimedia module 24 is powered via the system voltage112 and produces at least one output as shown in FIGS. 2 and 3. In thisillustration, only the headphone jack 52 output of the multimedia moduleis shown. As shown, a pair of headphones 110 may be coupled to theheadphone jack 52.

In operation, the processing module 20 executes an algorithm, as well befurther described with reference to FIGS. 8-12, to monitor the batteryusage by the handheld device and to ensure that, once the battery hasbeen as close to fully consumed as possible, the handheld device isfully shutdown or at least partially shutdown in a safe manner such thatwhen the battery is replaced, the handheld device will come upcorrectly. To facilitate the efficient battery use algorithm, theprocessing module 20 monitors the battery voltage, the system voltage112 and/or the current and/or voltage of each output of the multimediamodule 24, in this example the headphone jack 52. Typically, themonitoring of an output of the multimedia module 24 will be detectingwhether an overload condition, produced by a short circuit, and/orfaulty equipment coupled thereto, results in an excessive amount ofpower being drawn by that particular output. For example, if theheadphones were faulty such that they cause a short within the headphonejack 52, an overload condition would result. When an overload conditionresults, the processing module 20 disables the output for apredetermined period of time (e.g., one second to ten seconds). When thepredetermined period of time expires, the processing module 20 enablesthe output again and resumes monitoring for an overload condition. Ifthe overload condition persists, the output is again disabled. Thedisabling and enabling of the output may be done by a switch mechanismand/or by placing an output driver at a high impedance state to disable,for this example, the headphone jack 52. If the overload conditionpersists after several retries, the processing module 20 may cease tocontinue the retry and generate an error message for display on thehandheld device indicating that the particular output is experiencing anoverload condition.

The processing module 20 also monitors the system voltage 112 for asystem low voltage condition. A system low voltage condition resultswhen, for example, the desired system voltage 112 is 3.3 volts and dropsfrom the 3.3 voltage by a few percentile or more. The tolerance for thelow system voltage condition may be relatively small (e.g., a fewpercent voltage drop) based on how well the output(s) of the DC-to-DCconverter 26 are regulated. The less well regulated the output supply ofthe DC-to-DC converter is, the greater the tolerance needs to be for thelow system voltage condition. The drop in the system voltage 112 mayinclude or exclude load transients that cause ripple on the output ofthe DC-to-DC converter 26.

When a low system voltage condition arises, it is indicative that theamount of power being consumed by the handheld device is beyond theremaining power capacity of the battery 14 but is not causingdangerously low output voltages to be generated, which might result inan unsafe shutdown of the handheld device. In this instance, theprocessing module may disable one or more of the outputs of the handhelddevice, store the current settings of operation of the handheld device(e.g., volume setting, which particular song is being played from an MP3storage file, bass settings, treble settings, et cetera). Once thesesettings have been stored, the handheld device is shutdown such thatwhen the battery is replaced and the handheld device is reactivated, theoperation continues where it left off. Alternatively, the processingmodule may shutdown only a portion of the handheld device. For example,the processing module for the low system voltage condition may shutdownthe headphone jack which is a primary consumer of power for the handhelddevice but still allow for data file transfers and/or other low powerconsuming activities.

The processing module 20 also monitors the battery voltage. Typically,if the battery voltage drops below a particular threshold, in light ofthe monitoring of the system voltage 112 and the overload condition ofone or more outputs, it is indicative that the battery is not makingadequate contact with the power terminals of the handheld device thusappearing as no battery is present. When this condition is detected, theprocessing module stores essential settings corresponding to theexecution of a functional algorithm being performed and shuts down thedevice. In this manner, the algorithm is terminated in a predictablemanner, as opposed to crashing the algorithm, thus, when the device isrestarted, the algorithm can be predictably be restarted.

FIGS. 6 and 7 illustrate graphs regarding power consumption of abattery. As shown in FIG. 6, battery consumption is plotted versusbattery voltage. As the battery consumption approaches 100%, the batteryvoltage drops. The goal of the processing module 20 of FIG. 5 is to takethe battery consumption as close to 100% as possible without damagingthe software stored within the handheld device, which may occur if thehandheld device loses power and does not shutdown in a safe manner. Assuch, by monitoring multiple points within the handheld device, thedevice may be shutdown in a safe manner while taking the batteryconsumption as close to 100% as possible.

FIG. 7 is a graph that plots voltage versus power consumption for CMOSintegrated circuits. As shown, as the supply voltage increases the powerconsumption of an IC increases nonlinearly, which increases consumptionof the battery (i.e., reduces battery life). Thus, the processing modulemonitors the battery voltage as the battery consumption is increasedand, based on the power consumption of an IC versus supply voltagecurve, determines how much power of the battery is left to power thehandheld device. Based on the known amount of power available in thebattery versus how much power is consumed by each of the portions of thehandheld device, including the outputs, the processing module maydetermine whether the entire handheld device needs to be shutdown oronly a portion thereof when a low system voltage condition is detected.

FIG. 8 is a logic diagram of a method for efficient battery use by ahandheld device. As shown, the process begins at Step 120, 122 and 124.As one of average skill in the art will appreciate, the efficientbattery use by a handheld device may include one or more of theprocessing Steps 120, 122 and 124 and their associated steps.

At Step 120, at least one output of the handheld device is monitored foran overload condition. The process then proceeds to Step 126 where adetermination is made as to whether an overload condition occurs. Ifnot, the process loops back to the beginning of Step 120. Note that anoverload condition may be detected by determining the output currentprovided to the particular output and when the output current exceeds athreshold indicating the overload condition.

If, however, an overload condition occurs, the process proceeds to Step128 where a fail-safe algorithm regarding the overload condition isenabled. Such a fail-safe algorithm may be implemented as shown in FIG.9.

At Step 138 of FIG. 9, the overload condition fail-safe algorithm beginsby disabling the at least one output for a predetermined period of time(e.g., at least one second). The process then proceeds to Step 140 whereafter the expiration of the predetermined period of time, the at leastone output is enabled. The process then proceeds to Step 142 where theat least one output is monitored again for an overload condition. If anoverload condition persists, the processing module may generate an errormessage indicating the overload condition.

Returning to the logic diagram of FIG. 8, at Step 122 a processingmodule monitors a system voltage produced by the DC-to-DC converter fora system low voltage condition. The process then proceeds to Step 130where determination is made as to whether the low system voltagecondition exists. If not, the process reverts to Step 122. Note that thesystem low voltage condition may be determined by determining loading onone or more outputs of the DC-to-DC converter, determining the availablepower duration based on the loading and on the battery voltage, and,when the available power duration is less than the power availablethreshold, indicating the low system voltage condition. This wasillustrated and discussed with reference to FIGS. 6 and 7.

If a low system voltage condition exists, the process proceeds to Step132. At Step 132 the processing module enables a fail-safe algorithmregarding the low system voltage condition. The fail-safe algorithm forthe low system voltage condition may be implemented as shown in FIG. 10and/or FIG. 11.

In FIG. 10, the fail-safe algorithm begins at Step 144 where at leastone output of the handheld device is disabled. The process then proceedsto Step 146 where the current settings correspond to execution of atleast one functional algorithm is stored. The functional algorithm maybe playing of an MP3 file, recording an MP3 file, data transfer etcetera. Thus, the particular settings of the current execution of thisalgorithm are stored such that the algorithm may be shutdown in a safemanner without corruption. The process then proceeds to Step 148 wherethe handheld device is shutdown.

FIG. 11 illustrates an alternate fail-safe algorithm for the low systemvoltage condition. The processing begins at Step 150 where a portion ofthe handheld device is disabled. The process then proceeds to Step 152where current settings corresponding to the execution of at least onefunctional algorithm related to the particular portion that has beendisabled, are stored. The process then proceeds to Step 154 where theoperation of the handheld device continues in a limited, low powerconsumption mode.

Returning to the logic diagram of FIG. 8, at Step 124, the processingmodule monitors the voltage of the battery for a battery low voltagecondition. The process then proceeds to Step 134 where a determinationis made as to whether a low battery voltage condition exists. If not,the process loops back to Step 124. If, however, a low battery voltagecondition exists, the process proceeds to Step 136 where a fail-safealgorithm regarding the low battery voltage is enabled.

FIG. 12 illustrates an example of a fail-safe algorithm for a lowbattery voltage condition. The process begins at Step 156 whereessential current settings correspond to execution of at least onealgorithm are stored. The process then proceeds to Step 158 where thehandheld device is shutdown.

As one of average skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term. Such anindustry-accepted tolerance ranges from less than one percent to twentypercent and corresponds to, but is not limited to, component values,integrated circuit process variations, temperature variations, rise andfall times, and/or thermal noise. As one of average skill in the artwill further appreciate, the term “operably coupled”, as may be usedherein, includes direct coupling and indirect coupling via anothercomponent, element, circuit, or module where, for indirect coupling, theintervening component, element, circuit, or module does not modify theinformation of a signal but may adjust its current level, voltage level,and/or power level. As one of average skill in the art will alsoappreciate, inferred coupling (i.e., where one element is coupled toanother element by inference) includes direct and indirect couplingbetween two elements in the same manner as “operably coupled”. As one ofaverage skill in the art will further appreciate, the term “comparesfavorably”, as may be used herein, indicates that a comparison betweentwo or more elements, items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1.

The preceding discussion has presented a method and apparatus forefficient battery use by a handheld device. By monitoring multiplepoints within the handheld device, the battery life may be extended byutilizing the battery as close to 100% of its capabilities as possible.As one of average skill in the art will appreciate, other embodimentsmay be derived from the teaching of the present invention withoutdeviating from the scope of the claims.

1-30. (canceled)
 31. A circuit for use by a multifunction handhelddevice, the circuit comprising: a processing module that executes storesoperational instructions that cause the processing module to: receive,when coupled to the host device via a host interface, a plurality ofdigitally formatted files from a host device and store the plurality ofdigitally formatted files in a memory, power the handheld by the hostdevice when coupled to the host device via the host interface; playbacka selected one of the plurality of digitally formatted files, theplayback including the generation of an audio output; monitoring for alow voltage condition produced by a low battery voltage; when the lowvoltage condition is detected, enabling a first fail safe algorithm to:store settings corresponding to the selected one of the plurality ofdigitally formatted audio files; and shutdown the multifunction handhelddevice; when the handheld device is reactivated, resuming the playbackat the selected one of the plurality of digitally formatted files. 32.The circuit of claim 31 wherein the host interface includes a universalserial bus (USB) encoder and USB decoder.
 33. The circuit of claim 31wherein the plurality of digitally formatted files includes at least onecompressed digital audio file.
 34. The circuit of claim 31 wherein theplurality of digitally formatted files includes at least one compresseddigital video file, and the operational instructions includeinstructions that cause the processing module to: drive a video displaydevice for playing the digital video file.
 35. The circuit of claim 31,wherein the operational instructions include instructions that cause theprocessing module to: monitor of the audio output for an overloadcondition; when an overload condition is detected and when the lowvoltage condition is not detected, enabling a second fail safe algorithmto: disable the audio output for a predetermined period of time; afterexpiration of the predetermined period of time, enable the audio output;and resume monitoring of the audio output for the overload condition.36. A circuit for use by a multifunction handheld device, the integratedcircuit comprises: a processing module that executes operationalinstructions that cause the processing module to: receive a plurality ofdigitally formatted files from a host device and store the firstdigitally formatted files in a memory; playback a selected one of theplurality of digitally formatted files, the playback including thegeneration of an audio output; monitoring for a low voltage conditionproduced by a low battery voltage; when the low voltage condition isdetected, enabling a first fail safe algorithm to: store an audiosetting corresponding to the playback; and shutdown the multifunctionhandheld device; when the handheld device is reactivated, enabling theplayback to resume, based on the audio setting.
 37. The circuit of claim36 wherein the audio setting includes a volume setting.
 38. The circuitof claim 36 wherein the audio setting includes a bass setting.
 39. Thecircuit of claim 36 wherein the audio setting includes a treble setting.40. The circuit of claim 36 wherein the playback of the selected one ofthe plurality of digitally formatted files includes playback of aparticular song, and the audio setting includes the particular song. 41.The circuit of claim 36 further comprising a universal serial interfaceand wherein the handheld device is powered by the host device whencoupled to the host device via the universal serial bus interface. 42.The circuit of claim 36 wherein the plurality of digitally formattedfiles includes at least one compressed digital audio file.
 43. Thecircuit of claim 36 wherein the plurality of digitally formatted filesincludes at least one compressed digital video file, and the operationalinstructions include instructions that cause the processing module to:drive a video display device for playing the digital video file.
 44. Thecircuit of claim 36, wherein the operational instructions includeinstructions that cause the processing module to: monitor the audiooutput for an overload condition; when an overload condition is detectedand when the low voltage condition is not detected, enabling a secondfail safe algorithm to: disable the audio output for a predeterminedperiod of time; after expiration of the predetermined period of time,enable audio output; and resume monitoring of the audio output for theoverload condition.
 45. A method for use in a multifunction handhelddevice, the method comprises: receiving a plurality of digitallyformatted files from a host device when coupled to the host device;playing a selected one of the first plurality of digitally formattedfiles, the playing including generating an audio output; monitoring fora low voltage condition produced by a low battery voltage; when the lowvoltage condition is detected, enabling a first fail safe algorithm to:store an audio setting corresponding to the playing of the audio output;and shutdown the multifunction handheld device.
 46. The method of claim45 further comprising: generating a second plurality of digitallyformatted files by digitally recording a voice sample.
 47. The method ofclaim 45 wherein the audio setting includes a volume setting.
 48. Themethod of claim 45 wherein the audio setting includes a bass setting.49. The method of claim 48 wherein the audio setting includes a treblesetting.
 50. The method of claim 45 wherein playing the selected one ofthe plurality of digitally formatted files includes playing a particularsong, and the audio setting includes the particular song played.
 51. Themethod of claim 45 wherein further comprising the step of: powering themultifunction handheld device by a host device when coupled to the hostdevice via a host interface.
 52. The method of claim 45 wherein theplurality of digitally formatted files includes at least one compresseddigital audio file.
 53. The method of claim 45 wherein the plurality ofdigitally formatted files includes at least one compressed digital videofile, and the method further comprises: driving a video display devicefor playing the digital video file.
 54. The method of claim 55, furthercomprising: monitoring of the audio output for an overload condition;when an overload condition is detected and when the low voltagecondition is not detected, enabling a second fail safe algorithm to:disable the audio output for a predetermined period of time; afterexpiration of the predetermined period of time, enable the audio output;and resume monitoring of the audio output for the overload condition.55. An method for use in a multifunction handheld device, the methodcomprising: receiving a plurality of digitally formatted files from ahost device when coupled to the host device, the plurality of digitallyformatted files including a digital video file; powering themultifunction handheld device by the host device when coupled to thehost device via the host interface; playing a selected one of theplurality of digitally formatted files, the playing including thegeneration of an audio output; monitoring for a low voltage conditionproduced by a low battery voltage; when the low voltage condition isdetected, enabling a first fail safe algorithm to: disable the audiooutput; store settings corresponding to the selected one of theplurality of digitally formatted audio files; and shutdown themultifunction handheld device.
 56. The method of claim 55 wherein, whenthe battery is replaced and the handheld device is reactivated, theplayback of the selected one of the plurality of digitally formattedfiles resumes where the playback left off.
 57. The method of claim 55further comprising: generating an additional digitally formatted file bydigitally recording a voice sample.
 58. The method of claim 55 whereinthe plurality of digitally formatted files includes at least onecompressed digital audio file.
 59. The method of claim 55 wherein thestep of playing a selected one of the plurality of digitally formattedfiles includes driving a video display device for playing the digitalvideo file.
 60. The method of claim 55, further comprising: monitoringof the audio output for an overload condition; when an overloadcondition is detected and when the low voltage condition is notdetected, enabling a second fail safe algorithm to: disable the audiooutput for a predetermined period of time; after expiration of thepredetermined period of time, enable the audio output; and resumemonitoring of the audio output for the overload condition.
 61. Themethod of claim 55 wherein playing the selected one of the plurality ofdigitally formatted files includes playing a particular song, and thesettings corresponding to the selected one of the plurality of digitallyformatted audio files includes the particular song played.